Britain’s deputy prime minister, Angela Rayner, admitted Wednesday that she had failed to pay enough property tax on a flat purchase, following days of growing pressure over the issue.

The 45-year-old said she had referred herself to the government’s ethics adviser and alerted the tax authorities, blaming the error on receiving “inaccurate” advice.

Rayner, who is also the minister for housing, told a Sky News podcast that the discovery prompted her to speak to her family about resigning.

“I’ve been in shock, really, because I thought I’d done everything properly,” she said.

“I relied on the advice that I received, and I’m devastated because I’ve always upheld the rules and always have felt proud to do that.”

Rayner, a frequent lightening rod for criticism from Britain’s right-wing media, has faced questions over her tax affairs following the purchase of the apartment in Hove, southern England.

She was reported to have saved £40,000 in stamp duty on the flat because she removed her name from the deeds of a separate property in her constituency, meaning the new apartment is the only property she owns.

She said she had sought advice from lawyers “which did not properly take account of” all the details of her personal situation, including a trust fund set up for her disabled. Therefore, she said, “I did not pay the appropriate stamp duty at the time of the purchase.”

Prime Minister Keir Starmer backed his deputy in parliament on Wednesday, saying he was “proud to sit alongside” her.

Rayner “has explained her personal circumstances in detail. She’s gone over and above in setting out the details,” Starmer told the House of Commons.

He added he knew “how difficult that decision was for her and her family, but she did it to ensure that all the information is in the public domain”.

Rayner left school with no qualifications after becoming pregnant at the age of 16.

She is a figurehead of Labour’s left wing and regularly tipped to become leader one day. AFP